Hi All, I own a 2005 Dodge Dakota SLT with the 4.7, with 53k miles. Truck has been great so far with no problems, until recently. When I am at a redlight with the a/c on, the RPM fluctuates between normal idle and sometimes even as low as 200, almost stalling. This does not happen when the truck is in drive at a stop, with A/C off. As soon as I come to a stop and put it in park however, the engine dips down immediately to around 500 and bounces up and down repeatedly until I either shut it off or put it back in gear. Any ideas on what this could be? I was thinking the IAC

Thanks in advance, you all are a tremendous help

 

Id look for a vacuum leak, tps or IAC. If you need an IAC, I have one from Mopar with 3k on it and Ill sell it for a decent offer. I had issues and ended up buying 2 thinking it was the IAC still being the problem.

First, do a visual inspection under the hood. Sometimes it could be something simple. Id also take a can of brakeleen and spray around the engine bay. Those sensors can get expensive depending on your budget and it sucks when you buy one and it doesnt fix the problem.

 

+1 on the IAC being dirty. I had the same problem when I first got my truck. I thought the TB looked clean until I took it off.
You could try to just take out the IAC and clean it well (plunger seat area will more than likely be dirty).

 

anybody got a picture of the IAC so I know what to take off?

 

These are from my first TB swap:
2010-06-02_220247.jpg
Its the sensor toward the bottom right of the photo:
2010-06-02_221305.jpg

 

P.S. PLEASE remember to wear eye protection when spraying your IAC. I am one of those "whatever" guys, but came pretty close to getting an eyeful of TB cleaner.

Also, have an old toothbrush handy, it helps to scrub away the grime.

 

I had a similar issue except the A/C on part and I cleaned my TPS and it has been great ever since.

 

did you make a thread on how you did that, with before and after pictures? i have the rough idling issue but not as bad as you describe. mine is around 700rpm or so then drops to make 500 at the worst when it starts shaking real bad

 

man idk what it is bout october..but trucks are just messin up! my dad told me today that an 18 wheeler picked up a few rocks and riddled the hood and busted the windshield! hes paying for the windshield but says that its just dents in the hood i'll be alright! lol thanks dad

 

I just ordered a new Air temp sensor, Idle Air Control valve and a Throttle position sensor for Rock auto for about $100. Gonna just change them all. Truck just passed the 100K mile mark and has the spastic idle shakes.... I sea foamed it last week and it runs much much better now, but the idle is flaky still